Method for the non-cutting production of a hub of a transmission component possessing the hub

ABSTRACT

This invention concerns a method and device for the non-cutting production of a hub (27) for a transmission component. A sheet blank (21) which is carried by a tool (3) on a main spindle (4) and rotated relative to one or more presser rollers (9, 10) is formed to produce a cylindrical prominence (7), projecting from the sheet by pressing it with a presser roller round a pin (5) mounted on the tool or a mobile stop (8) and passing through said sheet.

The invention relates to a method for the non-cutting production of ahub of a transmission component possessing the hub from a sheet metalblank.

Transmission components designed as gear rings or designed as beltpulleys, especially poly-V-belt pulleys, are used in large numbers inautomobile construction and nowadays they are often produced, startingfrom a round plate, by spinning methods. The formation of the toothingsand/or the grooves is likewise possible by the spinning method, whereasthe fitting of the necessary hub presents difficulties. The actual hubis, in the region of the axis of rotation, a sleeve-shaped part of therotating pulley, said sleeve-shaped part making the connection with thepushed-through shaft or axle or with a journal.

Such a component is represented and described by way of example in U.S.Pat. No. 2,696,740.

The hub of a transmission component is produced, in the state of theart, by connecting a prefabricated cylindrical sleeve part to thetransmission component, conventionally four methods being employed forthe connection, namely, on the one hand, soldering of the twocomponents, welding of the two components, the connection of the twocomponents by frictional welding and, finally, it is possible also toproduce the transmission component by means of a forging method.

The three first-mentioned procedures have the disadvantage that anadverse influence on the actual transmission component occurs as aresult of the absolutely essential heat treatment, and, when weldingtakes place, subsequent machining of the weld seam is required. The costoutlay for producing the hub as a lathe-turned part is relatively high.

The distortion of the transmission component caused by the heattreatment must subsequently be removed again by means of certainmachining methods.

The reject rate of transmission components from such a production linewhich are not true-running is very high.

The use of forged transmission components is cost-intensive and,moreover, an undesirable metal hardening occurs, that is to say thestructure is changed, so that the subsequent application of theprofilings of the transmission component, whether as a gear ring or asgrooves for belt pulleys, becomes extremely difficult. Finally, thesurface of this transmission component scales, thus necessitatingadditional machining steps.

In summary, therefore, it can be stated that the previous outlay forfixing a hub to a relatively small transmission component is very high,that the reject rate during manufacture is high, and undesirableinfluences on the material occur which may be detrimental to the usefullife of the transmission component.

It is known from the literature reference "Blech, Rochre, Profile 1980"["Sheet Metal, Tubes, Profiles 1980"], page 660, to produce outer diskcarriers as a sheet-steel formed part, these outer disk carriers beingmanufactured in two pressing passes. Altogether, 27 processing steps arerequired to produce such an outer disk carrier. They comprise 10drawing, 7 calibrating, ironing and 7 cutting operations as well as 1upsetting operation. As a result of the drawing work, the structure istorn apart, that is to say the material structure is fatigued. Moreover,drawing operations are normally associated with inaccuracies which canhave an adverse effect in the case of a transmission component.

The object on which the invention is based is to simplify the method ofthe relevant generic type and to carry it out in one work cycle, withoutundesirable influence on the material structure of the transmissioncomponent occurring.

This object on which the invention is based is achieved by means of theteaching of the main claim.

A device for carrying out this method is explained in the subclaim.

This object on which the invention is based is also achieved by means ofthe teaching of patent claim 3. A device for carrying out the method isexplained in subclaims 5 and 6.

In other words, in contrast to the state of the art, and excluding thealready mentioned forging methods and drawing methods for producing thetransmission component, a one-piece transmission component is obtained,in which, by means of appropriate spinning measures, the transmissioncomponent is obtained from the round plate rotating about an axialshaft, with the hub being produced simultaneously.

It is not only possible here to ensure that the hub of the transmissioncomponent is produced in one work cycle, but it is possible, at the sametime, for the wall thickness of the hub to be higher or larger than thewall thickness of the sheet metal blank of the transmission component,so that the necessary strength for transmitting the torque is achievedhere.

Starting from a round plate, the hub is formed on the belt pulleyintermediate product in one set-up on a spinning machine. When themethod is employed, there is the possibility of producing belt pulleyintermediate products for all known methods of producing belt pulleys,since the thickness in the contour region and in the profile region ofthe belt pulley intermediate products is fixed by the spinning methodemployed.

Examples of the execution of the methods according to the invention areexplained below by means of the drawings. In the drawings

FIG. 1 shows a clamped cap in a spinning device,

FIG. 2 shows the deformation of the cap by spinning rollers,

FIG. 3 shows the forming of the special cylindrical hub part by formingrollers,

FIG. 4 shows the stage of final deformation by the use of thickeningrollers to obtain the cylindrical hub part,

FIG. 5 shows a sheet metal blank inserted into a spinning device,

FIG. 6 shows the deformation of the sheet metal blank to fix the latterto the tool,

FIG. 7 shows a step of the spinning method, in which the wall thicknessof the transmission component is reduced and forming of the hub isthereby achieved simultaneously, and

FIG. 8 shows the final stage of the spinning method, with the hubformed, and

FIG. 9A to F shows a basic diagram of possible versions of belt pulleyintermediate products with different thicknesses and hub positions.

FIGS. 1 to 4 show a cap 2 which is fixed to a tool 3 of a main spindle 4by means of a clamping chuck 15 belonging to the tool 3. The tool 3 hasa tool pin 5 Which projects centrically in the axial direction and whichbears or comes to bear on the inside of the clamped cap 2, a movablestop 8 bearing on the outside of the cap 2.

The orientation of the flanges 16 and 17 which adjoin the cap 2 andwhich, in the representation of FIG. 1, run parallel to the tool pin 5and to the axis of the main spindle 4 is unimportant.

The double arrow F marked in FIG. 1 indicates the direction of movementof the main spindle 4 and movable stop 8 for the purpose of fixing thecap 2.

FIG. 2 shows that the cap 2 is deformed in the direction of thecylindrical tool pin 5 as a result of the engagement of spinning rollers9 and 10, the deformation then being continued, by the use of a formingroller 11 shown in FIG. 3, until the cap has been folded round the toolpin 5. During this process, the cap 2 has partially come to bear as around plate 6 against the top side of the tool 3, whilst the remainingpart of the cap 2 has been laid around the tool pin 5 in a corrugatedmanner according to FIG. 3.

When, as shown in FIG. 4, this corrugated region is then compressedaround the tool pin 5 by thickening rollers 12 and 14, a cylindricaldesign of that part of the cap 2 then serving as a hub is obtained, andthe wall thickness of this cylindrical projection 7 can be larger thanthe wall thickness of the round plate.

Of course, in this stage of the method, it is possible, by retractingthe movable stop 8, to ensure that the material flows out towards thefree end of the tool pin 5, so that it is also possible to make the wallthickness of the cylindrical projection 7 smaller than the wallthickness of the round plate 6.

The feed direction of the thickening rollers 12 and 14 is represented bythe arrows F₂ in FIG. 4.

In summary, it may be stated that the proposal according to theinvention affords a cost-effective production method for transmissioncomponents equipped with a hub, no structural changes being causedwithin the transmission component during its production, there being thepossibility, at the same time, of giving the hub any wall thickness.

Proceeding from FIG. 4 of the foregoing explanations, it is nownecessary to open the cylindrical projection 7, so that the latter canreceive a shaft or a journal. The opening of the cylindrical projectioncan take place either by cutting off the bead, evident in FIG. 4, of thecylindrical projection 7, but it is also possible to open the end wallof the cylindrical projection 7 by means of bores or the like, so thatthe hub finally obtained then has the bead which contributes tostrength. After this production method, the machining of the flanges 16and 17 for the formation of the transmission component can then becarried out.

In FIGS. 5 to 8, 21 denotes a sheet metal blank which is arranged on atool located on a main spindle 22, in that, in the exemplary embodimentillustrated, the tool 23 carries a tool pin 24, onto which the sheetmetal blank 21 can be placed by means of a hole provided centrically inthe sheet metal blank. 25 denotes a movable stop which is movable to andfro and which, in its working position, comes into contact with the toolpin 24. The movable stop 25 has, in the region towards the sheet metalblank 21, an outside diameter which is larger than the outside diameterof the tool pin 24, thereby providing an abutment, designated by 34 inthe drawing, onto which the inner part of the sheet metal blank can cometo bear during the deformation of the latter.

29 denotes a clamping chuck which cooperates with the tool 23 and which,after a spinning roller 26 has bent round the outer edge region of thesheet metal blank, fixes this edge region of the sheet metal blank 21,so that the sheet metal blank is thereby prevented from creeping out.

The spinning roller 21 can be moved towards the tool pin 24 in thedirection of the arrow marked in FIG. 6 and at the same time, as shownparticularly clearly in FIG. 7, reduces the mean wall thickness of thesheet metal blank 21, the material displaced by the spinning roller 26flowing into the space present around the tool pin 24 and, as shownclearly in FIG. 8, coming to bear against the abutment 34, therebyproviding a cylindrical projection 28 which forms the actual hub 27according to FIG. 9 in the belt pulley intermediate product.

It can be seen from the drawing, particularly by comparison with FIGS. 6and 8, that the edge region of the sheet metal blank 21, said end regionbeing fixed by the clamping chuck 29, is thicker than the middle edgeregion of the sheet metal blank 21, and that, once again, thecylindrical projection 28 has a substantially larger material thicknessthan the middle edge region of the sheet metal blank 21. This wallthickness of the cylindrical projection 28 can be determined as afunction of the size of the space between the abutment 34 of the movablestop 25 and the outside of the tool 23.

The follow-up roller 35 shown in FIGS. 7 and 8 prevents the material ofthe sheet metal blank 21 from being bent upwards during the spinningprocess.

FIG. 9 represents by items A to F possible versions of belt pulleyintermediate products with different thicknesses and hub positions. Ifthe belt pulley is to have a contour region K and, if appropriate, aperforation 11, as shown under E and F, this contour region, ifappropriate together with the perforation, can easily be produced on apress from the belt pulley intermediate product produced by the spinningmachine. There is, furthermore, the possibility of producing simplecontour regions directly on the spinning machine by means of additionaltool carriers.

In summary, therefore, it can be said that the spinning methodsaccording to the invention have the following advantages in relation tothe production method known hitherto:

1. Less use of machinery,

2. the material structure of the belt pulley intermediate productundergoes no adverse influences, such as, for example, during weldingand forging,

3. the hub inside diameter can be produced by means of the spinningmethod without subsequent rolling,

4. there are no disadvantages during the profiling of the belt pulley asa result of previous work cycles,

5. there is the possibility of producing grooves or toothings on the hubinside diameter by means of the spinning method, without subsequentmachining, as is evident, for example, from representation F in FIG. 9,in which the draw-off groove 32 can be produced during the spinningprocess.

I claim:
 1. Method for the non-cutting production of a hub of atransmission component possessing the hub from a sheet metal blank, thesheet metal blank being formed into a cap, characterized in that the cap(2) is deformed by spinning around a central tool pin (5) into acylindrical projection (7) projecting from a round plate (6) and thecylindrical projection (7) is subsequently opened in order to receive acoaxial shaft.
 2. Device for the non-cutting production of a hub of atransmission component possessing the hub from a sheet metal blank, thesheet metal blank being formed into a cap, comprising a tool (3) carriedby a main spindle (4), with a tool pin (5) and a clamping chuck (15) anda movable stop (8) which is arranged opposite the tool pin (5) andwhich, together with the tool pin (5) and the clamping chuck (15), fixesa cap (2), and spinning rollers (9, 10), forming rollers (11) andthickening rollers (12, 14) which successively load said cap (2). 3.Method for the non-cutting production of a hub of a transmissioncomponent possessing the hub from a sheet metal blank, characterized inthat the sheet metal blank (21) carried by a tool (23) of a main spindle(22) and rotating relative to one or more spinning rollers (26) isreduced in thickness by spinning by means of the spinning roller (26),and the material thus obtained is deformed into a cylindrical projection(28), projecting from the sheet metal blank (21), around a tool pin (24)passing centrically through the sheet metal blank (21).
 4. Methodaccording to claim 3, characterized in that the tool pin (24) isarranged on the movable stop (25).
 5. Method according to claim 3,characterized in that the tool pin (24) is arranged on the tool (23). 6.Method according to claim 3, characterized in that the edge region ofthe sheet metal blank (21) is fixed before the spinning process whichreduces the thickness is carried out.
 7. Device for the non-cuttingproduction of a hub of a transmission component possessing the hub froma sheet metal blank, comprising a tool (23) carried by a main spindle(22), with a centric tool pin (24) and a clamping chuck (29) loading theedge region of the sheet metal blank (21) and a movable stop (25) whichis arranged opposite the tool pin (24) and the outer circumference ofwhich is larger than the outer circumference of the tool pin (24) and ofwhich the side directed towards the sheet metal blank (21) terminates ata distance from the sheet metal blank (21) and thus forms a space bymeans of an abutment (34), and at least one spinning roller (26) movableparallel to the plane of the sheet metal blank (21) towards the centerof the sheet metal blank (21).
 8. Device according to claim 7,characterized by a follow-up roller (35) taking effect simultaneouslywith the spinning roller (26).